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First Light AO System for LBT

“ Astronomical telescopes and Instrumentation ” 22-28 August 2002, Waikoloa, Hawaii, USA. First Light AO System for LBT. S. Esposito a , A. Tozzi a , D.Ferruzzi a , M.Carbillet a , A.Riccardi a , L.Fini a , C. Verinaud a , M.Accardo a , G.Brusa b , D.Gallieni c , R.Biasi d ,

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First Light AO System for LBT

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  1. “Astronomical telescopes and Instrumentation” 22-28 August 2002,Waikoloa, Hawaii, USA [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 First Light AO System for LBT S. Espositoa, A. Tozzia, D.Ferruzzia, M.Carbilleta, A.Riccardia, L.Finia, C. Verinauda, M.Accardoa, G.Brusab, D.Gallienic, R.Biasid, C. Baffaa, V.Biliottia, I. Foppianie, A. Puglisia, R. Ragazzonia, P.Ranfagnia, P. Stefaninia, P. Salinaria, W. Seifertf, J.Stormg a Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy bSteward Observatory, University of Arizona, USA cADS International, Corso Promessi Sposi 23/d, 23900 Lecco Italy dMicrogate Srl, Via Kravogl 8, 39100 Bolzano, Italy eDipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna, Italy f Landessternwarte, Königstuhl 12 D-69117 Heidelberg, Germany gAstrophysikalisches Institut Potsdam, An der Sternwarte 16, D - 14482 Potsdam, Germany Presented by: S. Esposito, Arcetri Observatory, INAF

  2. [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Talk Overview System location & key features Pyramid Wavefront Sensor Opto-Mech. WFS positioning & stability System Architecture & Real-time operations System Performance Simulations Project situation & Time schedule

  3. See 4837-15 LGS LUCIFER window LUCIFER [4841-103], W. Seifert NGS AGW [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 System Overview & Location

  4. [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 System Key features Adaptive Secondary mirror: LBT672[4839-85], A. Riccardi Improves AO channel transmission ~ 40% (WFS) Actuators pitch ~ 28cm ~ ro @ 0.75 mm, (0.8” seeing V Band) effective correction down to sensing wavelenght Pyramid wavefront Sensor (PS) Better performance WRT Shack-Hartmann > 1 mag Pupil sampling adjustable using on-chip binning, LBT 30x30,15x15,10x10... Moveable WFS Allows use of small refractive optics, 32mm Ø max. Reference star acquisition on a 3x2 arcmin FOV Small AOS opto-mechanics 320x400 mm (20 kg) Reduces costs, flexures, turbulence.....

  5. 320mm 400mm [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 WFS Opto -Mechanical design Two WFS optical path: Pyramid sensor optical path: blue, 500mm, [0.6-0.9 mm] Tech./Acquisition camera: red F/15 LBT beam reflected on LUCIFER 15° window (1) Fixed telecentric lens, 80mm ø 2 arcmin FOV, (3x2 arcmin) (2)Refocusing triplet, 32mm ø (5) Fast steering mirror: ± 0.8” (PI) (6) Pupil Rotator (8)Refractive pyramid, 2.5” FOV ø (9)Camera triplet, 10mm ø (10) Pyramid sensor CCD (12) Technical/acquisition camera max FOV 30 arcsec ADC (4) Four on-board motorized parts (3),(4),(6),(9)

  6. f/45 incoming beam after refocusing. triplet Marconi CCD 39 chip side dimension 1/f-number • CCD39 pixel size = 24 mm • Camera triplet f = 35mm • 30 pixel on pupil diameter • 6 pixel minumum pupil sep. • Pyramid FOV > 2.5” • Pupil distorsion < 1 mm in a 1 arcsec FOV Scrathed area ~ 4 mm Sensor DL PSF~ 34 mm Energy loss < 10% Pyramid WFS channel 72% t Chromatic correction using two different glasses f/45 beams Minimum pupils packing: 2° pyramid base angle at f/45 20 mm Pyramid scratched edges See poster [4839-36], E. Diolaiti [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Pyramid optical design

  7. SciMeasure Analytical Systems, Inc. Pixel Noise vs. fps and binning x2 x1 x3 x5 x4 Average QE in sensing band (0.6-0.9 mm) is 0.81% (DD chip) and 0.59% (std. chip) [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Pyramid Sensor detector Based on the Marconi CCD39 chip Basic LBT pupil sampling is 30x30 On chip binning 15x15,10x10 Four pixel rate 150,400,850,2500KPixel/s RON 3.5-8.3 e- Dark Current 100 e- /s/pixel @ -40° dithering option Arcetri&Bologna Observatory joint project to develope a camera system using the LLLCCD60 (128x128, RON <1e- @ 1000 fps) . [See late poster, I. Foppiani]

  8. 3 Tel. Pointing 0°, 25°,50° (ZD) 8 derotator pos. 0°,90°,180°,270° (+15°) Y X Z [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 WFS positioning & stability X: U200-200mm, 110mm free travel Y: U200-100mm, 80mm free travel Z: U300-200mm, +50,-30 mm free travel Ball screw 2.5mm 0.1/0.5 micron optical encoder end of travel & home 15°/h derotator speed, 15 min. obs.  3.1 mas 1/10 LUCIFER DL PSF @ 1.25 mm NIR LUCIFER TILT: 3 min sampling rate LBT: 104phot./ min, H mag 20

  9. [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Pupil Images position & Stability Pupil position error budget (1) (7) (2) Consider camera triplet Fold mirror < 5”  Pupil rotator < 4”,6mm (Micos Gmbh) On board misalignment : 10”, 20 mm Board misalignment: 32”, 92 mm (FEA) LUCIFER window: 32”, 92 mm (8) Overall Error ~ 3 mm 1/8 of subaperture @ 30x30 (6) (9) Rates for rays rms in mm/mm and mm/arcsec

  10. 947 ms 1004 ms CCD read - out CCD read-out 4x2.5MPixel/s DT ~ 1.0 read-out time DM Commands comp. 57ms 460ms 920ms Start slope computation Engineering User interface Slope computation (250ms) Data transfer to M2 27ms) BCU See [4839-91], R. Biasi M2 LBT Crates CCD39 80x80 pixels 72 IO lines See [4839-91], R. Biasi TCP – UDP over Ethernet Fiber comm. 2Gb/s Prog. logic Dedicated protocol over fiber link SciMeasure Controller DMA DSP DM [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 System architecture & Real-Time Operation

  11. [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 System performance simulations I [see late poster M. Carbillet]

  12. [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Sistem performance simulations II 15x15 Max SRs: 87,93,96 10x10 30x30 SR 0.2, mR = 14.3, 15.5, 16.7 On-Axis SR 20 % Max off-axis 30 arcsec SR 0.2, mR = 15.5 (SH), 16.7(PS)

  13. DR SciMeasure Analytical Systems, Inc. WFS HO [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Current situation & schedule AO system HW cost: 300K USD (two units) Manpower: 10 person / year (two years) People involved: ~ 8-10 people AO system parts acquisition: Oct/Nov 2002 P45+PWFS+RTR lab test: 4Q 2002 -1Q 2003 LBT672+PWFS tower test: 4Q 2003 -1Q 2004

  14. [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002 Conclusion First light AO system for LBT Adaptive secondary mirror: LBT672 Pyramid Wavefront sensor: (30x30,15x15,10x10) Moveable WFS, FOV 3x2 arcmin, 320x400mm Opt. design, mech. design, FEA, RT HW, simulations.. Mag lim gain > 1mag WRT Shack-Hartmann Sky Coverage doubled, 11%(J), 33%(H), 87%(K) System suitable components identified and ordered. Final System test completed in 4Q 03, 1Q 04.

  15. First light AO system for LBT [4839-20], Astronomical Telescope and Instrumentation, 22 August 2002

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